The Cytogenetics Core Facility provides cytogenetics, molecular cytogenetics, and molecular clonality assays to City of Hope Cancer Center (CC) investigators. Primary services of this facility include: cell line characterization and verification of integrity, tissue (cell) culturtng, solid tumor cytogenetics, assays for genomic instability, fluorescence photomicroscopy, and fluorescence in situ hybridization (FISH) studies for aneuploidy detection, gene tracking, specific gene alterations, genotype/phenotype targeted FISH (T-FISH) analyses for residual disease testing, and gene integration/mapping studies. Spectral karyotyping or 24- color karyotyping, 20-color karyotyping for mouse model systems, and FICTION (fluorescence immunophenotyping and interphase cytogenetics as a tool for investigation of neoplasms) or T-FISH (sequential phenotypic followed by genotype analysis) are also available. Tyramide signal amplification FISH is used for the cellular localization of nucleic acids when target levels are suspected to be low; e.g., in gene or adoptive immunotherapy studies. Due to CC members' needs, we expanded our services to provide (1) clonality testing to monitor for clonal hematopoiesis, a precursor of therapy-related acute myelogenous leukemia/myelodysplasia observed in some patjents who received dose-intensive regimens; and (2) Bacterial Artificial Clones (BAG) arrays (aCGH) for comprehensive molecular karyotyping. We also provide imaging analysis training for scientists who wish to screen their own studies or who require extensive usage. Finally, this core is also the reference FISH core laboratory for the SWOG cytogenetics program. During the most recent 12-month reporting period, the Cytogenetics shared resource was used by 18 Cancer Center members from all 5 Research Programs. Peer-reviewed usage represented 97% of total usage. Annual budget for this core is $292,811, of which 22% is institutional funding, 22% is user fees. 26% is from other sources, and 29% is requested from the CCSG.